Everything in your last pic looks like melanistic ringneck to me. I have quite a few that look just like that. They will turn out something like this if they are roosters.
Ok if that is a melanistic mutant then what is this lol
Here is a photo of some Black Ringnecks and domestic Green Ringnecks.
The Blacks (Melanistic) are the BLACK babies with a yellowish white throat patch. The chick closest to the camera, and the one just to the left of it.
The green chicks are not black but have a dark chocolate tint to them- they may or may not have any white on them. The chick standing in the far left corner is easiest to use as a comparison to the black chicks.